Self-adjusting spherical bearing

ABSTRACT

A spherical bearing assembly having an inner race member and an outer race member, the inner surface of the outer race member being a concave spherical surface, the outer surface of the inner member being a complementary convex spherical surface, the inner member including a spool member having double frusto-conical portion disposed on its outer surface and at least three spherical segments, each segment having a double frusto-conical depression on its inner surface complementary to said double frusto-conical portion, said segments disposed on and interlocked with said spool member by the registration of said double-frusto-conical depression on said double frusto-conical portion.

This copending application is a continuation of application Ser. No.440,472, filed Feb. 7, 1974, which is now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates generally to self-aligning bearings havinga ball-like inner member with a convex outer surface and an outer memberhaving an inner surface with a complementary concave spherical innerface. These types of bearings, which are commonly called "bearings" ,have been utilized in industry for a substantial period of time. Thetechnological evolution of these type bearings has been directed more inthe terms of material composition of its various component parts ratherthan toward basic changes in design concepts. Accordingly, the designadvances in spherical bearings have not been substantial in nature andthereby presently limiting their applications.

One area in which the spherical bearings have been extensively appliedis the aircraft industry. This is due to the spherical bearingself-aligning characteristic. A typical such application is marrying ofa spherical bearing to a landing gear strut or member of an airplane. Inthis application the outer race is commonly press-fitted and/or stakedinto a housing or the like rendering it difficult to remove and/ormaintain. When any such maintenance is required, such as replacing ofthe ball, the entire bearing assembly including the inner and outer racemember would have to be removed and replaced by an entirely new bearingassembly. Such an operation could entail substantial expense and downtime of the entire aircraft.

There are a number of prior art type spherical bearings which have beenaddressed to this kind of problem. One such type prior art bearing isthe "messerschmidt" bearing. A concept of this bearing is that the ballcan be removed in the field without disassembling the entire bearing,that is, removing the outer race member from its mounting. Themesserschmidt type spherical bearing has proved somewhat unsatisfactoryin that its overall bearing surface is decreased by the provision of aslot. This decrease or rather limited bearing surface area has a markednegative effect on the bearing performance characteristics.

SUMMARY OF THE INVENTION

It is therefore, a primary object of the present invention to provide aspherical bearing assembly having an inner race member and an outer racemember, the inner surface of the outer race member being a concavespherical surface, the outer surface of the inner member being acomplementary convex spherical surface, the inner member including aspool member having double frusto-conical portion disposed on its outersurface and at least three spherical segments, each segment having adouble frusto-conical depression on its inner surface complementary tosaid double frusto-conical portion, said segments disposed on andinterlocked with said spool member by the registration of said doublefrusto-conical depression on said double frusto-conical portion.

It is yet another object of the present invention to provide a sphericalbearing assembly which has a rotational redundancy. That is, the innermember is adapted to be rotatably mounted within the outer member. Afirst bearing surface between these two members being defined by theconvex outer surface of the inner member and the complementary concaveinner surface of the outer member. The rotational redundancy provided bythe spherical bearing of the present invention is the second bearingsurface between the inner surface of the segments of the inner memberand the outer surface of the spool member.

It is still another object of the present invention to provide aspherical bearing assembly in accordance with the present inventionwherein the spool member is provided with an symmetrical frusto-conicalportion dispjsed on its outer surface and at least three sphericalsegments, each segment having a symmetrical frusto-conical depression onits inner surface complementary to the frusto-conical portion rib on thespool member, the spherical segments disposed on and interlocked withthe spool member by the frusto-conical depression on the complimentaryfrusto-conical portion.

It is still another object of the present invention to provide aspherical bearing assembly in accordance with the present inventionwherein the frusto-conical portion is centrally disposed on the outersurface of the spool member.

It is yet another object of the present invention to provide a sphericalbearing assembly in accordance with the present invention wherein theregistration of the conical portion within the conical depressionmaintains the segments upon the spool member so as to mechanicallyinterlock them thereon when the member is in its operational position.

It is still another object of the present invention to provide aspherical bearing assembly in which the frusto-conical depression formedon the inner surface of the spherical segments are annular and in lineand form a continuous annular groove which is adapted to receive thefrusto-conical portion disposed on the outer surface of the spoolmember.

It is still another object of the present invention to provide aspherical bearing assembly in which there are three spherical segments,the segments providing substantially all of a first bearing surfacebetween the inner member and the outer member.

It is still another object of the present invention to provide aspherical bearing assembly in which the concave inner surface is coatedwith a self-lubricating plastic such as "Teflon" , a trademark of theDupont Corporation.

It is yet another object of the present invention to provide a sphericalbearing assembly in which the outer surface of the spool member iscoated with a self-lubricating plastic material such as Teflon.

It is yet another object of the present invention to provide a sphericalbearing assembly in which the outer surface of said inner member asdefined by the spherical segments are coated with self-lubricatingplastic such as Teflon.

It is still another object of the present invention to provide aspherical bearing assembly in which the frusto-conical depression isdisposed on the outer surface of the spool member and the frusto-conicalportion is formed by in-line annular grooves formed on the inner surfaceof the spherical segments.

Embodiments of the bearing according to the concept of the presentinvention are shown and/or described by way of example in theaccompanying drawings and following description of the invention withoutattempting to show or describe all of the various forms andmodifications in which the invention might be embodied; the inventionbeing measured by the appended claims and not by the details of thespecification.

FIG. 1 is a side elevational view of the spherical bearing assembly thepresent invention with the longitudinal axis of the outer race memberand the inner race member being substantially coincident;

FIG. 2 is a side elevational view of the spherical bearing assemblyembodying the present invention with the longitudinal axis of the innerrace member and the outer race member being substantially perpendicular,that is, the inner race member has been rotated substantially 90° in oneplane;

FIG. 3 is a front elevational view of the spherical bearing assembly ofFIG. 1;

FIG. 4 is a front sectional view taken along line 4--4 of FIG. 1;

FIG 5 is a front elevational view of the bearing of FIG. 2;

FIG. 6 is a front sectional view taken along line 6--6 of FIG. 2;

FIG. 7 is a perspective view of the inner race member alone in anassembled condition;

FIG. 8a,8b,8c illustrate a perspective view of the component parts ofthe inner race member of FIG. 7;

FIG. 9 is a perspective sectional view of the spherical bearing of FIG.1; and

FIG. 10 is a perspective sectional view of the bearing of FIG. 2 withone of the segments of the inner race member removed.

FIG. 11 is a sectional view of a modified form of the invention.

DESCRIPTION OF THE INVENTION

A spherical bearing embodying the concept of the present invention isgenerally indicated, as appropriate, by numeral 10 on the attacheddrawing as set forth in FIGS. 1 through 10, inclusive.

The bearing 10 has been shown as a spherical bearing, however, thepresent invention is also directly applicable to male or female rod endtype bearings and the like.

The spherical bearing 10 comprises an outer member 12 which may beprovided with an outer cylindrical surface 14. The outer member 10 mayalso be provided with two annular faces 16. The outer member 12 isfurther provided with a concave spherical inner surface 18. It may benoted at this jucture that the outer member 12 may be similar to theouter race members as found in the prior art.

The basic thrust of the present invention is to be found in the innermember which is formed, in the prior art, as a single solid member. Theinner race member 20 as distinguished from the inner members of theprior art is a composite member having several parts. The basic part ormember is the spool member 22. The spool member may be characterized asa spool member having an frusto-conical portion 24. The spool member 22and the frusto-conical portion 24, are so sized as to be able to beplaced within the surface defined by the concave inner surface 18 of theouter member 12. This can be best seen in FIGS. 2, 5, 6 and 10.

The spool member 22 and its various associated parts may be rotated suchthat its longitudinal axis is perpendicular to the longitudinal axis ofthe outer race member 12. When the spool member is rotated in such afashion that the convex outer surface of the inner race member 20 isexposed substantially all of the convex surface of the inner race memberwhich is formed and defined by at least three segments 26. There may beat least three equally sized segments 26 on the spool member 22. Thesegments 26 may each be provided with an frusto-conical depression 25which may be formed on in-line relation so as to define an annulardepression 25 complimentary to the frusto-conical portion 24 on thespool member 22. The interlocking relationship between thefrusto-conical depression 25 and the frusto-conical portion 24 maintainsthe postional integrity, in an axial direction, of the segments 26 onthe spool member 22. However, the segments 26 may be removed from thespool member 22 when the spool member is rotated in the above notedfashion. EAch segment 26 may be moved in turn from the spool member 22ultimately leaving the spool member completely devoid of the segments26. Thereafter, the spool member can be removed entirely from the outermember 12. It can be seen, therefore, that the inner member can becompletely dismantled and removed from the outer member 12 withoutdislodging or otherwise interferring with the position or the conditionof the outer member with respect to its mounting surface (not shown).This feature becomes particularly important when the outer face memberis fixedly attached to some structural surface such as by press-fit orthe like. For example, in an aircraft or machine tool type application,a new inner member may be inserted quickly and efficiently withoutdisturbing any other part of the aircraft or machine tool except thatpart which is directly attached to the inner race member 20.

An additional very important feature of the present invention is thatthe inner member can be sized by varying the dimension of the convexouter surface as defined by the segments 26. By varying this dimensioncertain bearing wear, which may be experienced by the inner concavesurface of the outer member 12, can be accommodated, thereby maintainingthe overall bearing tolerance of the bearing assembly 10.

An additional very important feature of the present invention is that itinherently embodies a second or redundant bearing surface. Inparticular, the inner surfaces 28 of the segments 26 and the outersurface 30 of the spool member 22 may define a second bearing surface.This bearing surface forms races which can become particularly importantin a situation where there may be interference between the inner memberand the outer member at the bearing surface defined by the concave innersurface of the outer member 12 and the convex outer surface of the innermember 20. Upon any such interference, which may be caused by corrosion,dirt or the like, the above noted second bearing surface between thespherical segments 26 and spool member 22 could then provide for adegree of movement. This movement can be further enhanced by treatingthe various surfaces with a self-lubricating plastic such aspolytetrafluoroethylene.

It is to be noted that frusto-conical portion 24 is depicted in thedrawings as being disposed centrally on the outer surface of the spoolmember 22 while the complimentary annular frusto-conical depression 25is disposed on the inner surface of the spherical segments. The positionof these elements could, of course, be reversed the frusto-conicalportion being disposed on the inner surfaces of the spherical segmentsand the complimentary annular frusto-conical depression disposed on theouter surface of the spool member. The axial position of the rib andgroove could also be changed form the central position.

As before mentioned, the present invention provides a marked improvementin the ability to service spherical bearings in the field withoutdisplacing or otherwise dislodging the outer race member. This isaccomplished without any compromise in the bearing performance orcharacteristic such as a reduction in the overall bearing surface whichis typified by the prior art bearings such as the messerschmidt typeball spherical bearing.

From the above description of the invention along with various figuresas set forth in the drawings it will be readily seen and appreciatedthat a spherical bearing embodying the concept of the present inventionwill positively and effectively accomplish the objectives of theinvention. The above-noted embodiment is shown by way of example withoutattempting to show all the various forms and modifications in which theinvention might be embodied; the invention being measured by theappended claims and not the specific details of the specification.

I claim:
 1. A spherical bearing assembly having an inner race member andan outer race member, the inner surface of the outer race member being aconcave spherical bearing surface, the outer surface of the inner memberbeing a complementary convex spherical bearing surface, the inner memberincluding a spool member having a frusto-conical portion disposed on itsouter bearing surface and at least three spherical segments, eachsegment having a frusto-conical depression on its inner bearing surfacecomplementary to said frusto-conical portion, said segments disposed onand held together to form other races with said spool member by theregistration of said fursto-conical portion in said complementaryfursto-conical depression, whereby the frusto-conical portion anddepression cooperate to provide rotational redundancy and positionalcentering of the segments on the spool.
 2. A spherical bearing assemblyin accordance with claim 1 wherein said frusto-conical portion iscentrally disposed on the outer surface of said spool member.
 3. Aspherical bearing assembly in accordance with claim 2 wherein there isdouble symmetrical frusto-conical portion.
 4. A spherical bearingassembly in accordance with claim 1 wherein said frusto-conical portionand said frusto-conical depression are annular and continuous.
 5. Aspherical bearing assembly having an inner race member and an outer racemember, the inner surface of the outer race member being a concavespherical bearing surface, the outer surface of the inner member being acomplementary convex spherical hearing surface, the inner memberincluding a spool member having a frusto-conical depression disposed onits outer bearing surface and at least three spherical segments, eachsegment having a frusto-conical portion on its inner bearing surfacecomplementary to said frusto-conical depression, said segments disposedon and held together to form other races with said spool member by theregistration of said frusto-conical portion in said complementaryfrusto-conical depression, whereby the frusto-conical portion anddepression cooperate to provide rotational redundancy and positionalcentering of the segments on the spool.